In recent years victims of renal disease have increasingly been assisted by use of the blood cleansing ability of kidney dialysis machines, which substitute for nonfunctioning kidneys. A small portion of the victim's blood is made to circulate, outside the body, through a fluid loop which is separated from a saline solution by an exceedingly thin membrane. The membrane is permeable to smaller molecules, such as urea, and impermeable to larger molecules, such as colloids. Accordingly, many of the poisons in the blood can be dialyzed across the membrane and discharged into the saline solution, thereby reducing the poison load in the bloodstream, without excessive loss of proteins, etc., from the patient's blood.
A typical example of a kidney dialysis machine is that of U.S. Pat. No. 3,878,095 for a DIALYSIS APPARATUS, issued to J. D. Frasier and A. Stevenson, Apr. 15, 1975. It will be seen from that disclosure that such a machine is complex and expensive.
In view of the high cost of kidney dialysis machines, it is the usual practice to use one machine for a number of patients in turn, often around the clock.
Between uses, the machine must be cleaned and also sterilized. This is usually done with sterilizing solutions, such as formaldehyde or chlorine, while a temporary shunt is connected as a substitute for the single-use dialysis membrane. For example, in the Frasier and Stevens patent a shunt 57 (labeled 56 in the drawing) is substituted for the Kiil dialysis member K, as explained in the patent, at column 10, lines 39 to 43. Hot water has also been used to sterilize kidney dialysis machines, as shown by the patents to A. U. Austin and R. S. Patch, U.S. Pat. Nos. 3,352,779, issued Nov. 14, 1967, and E. J. Serfass, J. E. Martin and W. E. Wilson, 3,441,136, issued Apr. 29, 1969.